Late radiation damage in prostate cancer patients treated by high dose external radiotherapy in relation to rectal dose.
A retrospective analysis of the incidence of radiation proctitis was performed in 154 patients with carcinoma of the prostate treated with external radiotherapy assisted by CT-scan planning from 1983 to 1985. An attempt was made to assess a dose-response relationship for proctitis. Multivariate Cox regression analysis showed that previous bowel disease or surgery, anterior rectal dose, and average rectal dose contributed to a higher risk of proctitis. The anterior rectal dose was the most important indicator. No statistically significant correlation was found for the posterior rectal dose. The actuarial 2-year incidence of moderate or severe proctitis was 22% for anterior rectal doses less than 70 Gy and 20% for anterior rectal doses between 70 and 75 Gy, but increased to 60% when the dose was more than 75 Gy. A dose effect relation was evident, with a sharp dose-response gradient around 75 Gy at the anterior rectal wall.
Smit
W G
WG
Department of Radiotherapy, Dr. Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
Helle
P A
PA
van Putten
W L
WL
Wijnmaalen
A J
AJ
Seldenrath
J J
JJ
van der Werf-Messing
B H
BH
D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011349:Proctitis / Q000453:epidemiology*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed